Revert "A few clarifications"

This reverts commit 8c4be93ba0ab8dcdddb25a8a43df3130f0b35ff3.
Implemented the constructor and the destructor

They should work the way I expect.
Implmented getNumItems()

It should work
Implemented add()

It should work
Implmented remove()
Debugged remove()

Used "circular array" strategy.
Added the return type for remove

Still need to debug
Implemented grow()

It's not working, so it need to be debugged.
Debugged grow()

Updated front, so I can copy a circular array.
Changed something
Merge pull request #41 from YangLi1/master

None